Often rather than airbushing people's image you want to actually increase the signs of aging on an image of someone's face.
This technique is used a lot in missing person cases and is a tool in the forensic artists arsenal (along with, for example, reconstructing faces from skulls) and is now as age progression,
As well as the obvious signs like wrinkles, grey/thinning/receding hair and a general loss of the skins elasticity there are also other changes that take place which are especially noticeable in the changes from childhood to adulthood like a thinning and lengthening of the face due to general growth of the skull and development of the teeth.
Clearly the more information the artist has on the subject the more accurate the image can be and pictures of other family members and possible information on health problems, etc. can help enhance the quality of what is after all an educated guess.
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Xel provided this sample image:
and docilebob had a play with it and the (impressive results) are:
Time - a photgrapher has taken pictures of himself and his family over the years and it documents beautifully the changes the face goes through over time.
